scholarly journals Floquet-enhanced spin swaps

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haifeng Qiao ◽  
Yadav P. Kandel ◽  
John S. Van Dyke ◽  
Saeed Fallahi ◽  
Geoffrey C. Gardner ◽  
...  
Keyword(s):  
Quantum Information Processing ◽  
Quantum Systems ◽  
Quantum Computers ◽  
Quantum Operations ◽  
Efficiency Of Algorithms ◽  
Order Of Magnitude ◽  
High Connectivity ◽  
Quantum Phenomena ◽  
Transfer Of Information ◽  
Time Crystals

AbstractThe transfer of information between quantum systems is essential for quantum communication and computation. In quantum computers, high connectivity between qubits can improve the efficiency of algorithms, assist in error correction, and enable high-fidelity readout. However, as with all quantum gates, operations to transfer information between qubits can suffer from errors associated with spurious interactions and disorder between qubits, among other things. Here, we harness interactions and disorder between qubits to improve a swap operation for spin eigenstates in semiconductor gate-defined quantum-dot spins. We use a system of four electron spins, which we configure as two exchange-coupled singlet–triplet qubits. Our approach, which relies on the physics underlying discrete time crystals, enhances the quality factor of spin-eigenstate swaps by up to an order of magnitude. Our results show how interactions and disorder in multi-qubit systems can stabilize non-trivial quantum operations and suggest potential uses for non-equilibrium quantum phenomena, like time crystals, in quantum information processing applications. Our results also confirm the long-predicted emergence of effective Ising interactions between exchange-coupled singlet–triplet qubits.

Quantum Polaritonic

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Phase Transitions ◽  
Quantum Information ◽  
Quantum Information Processing ◽  
Quantum Phase Transitions ◽  
Macroscopic Quantum ◽  
Quantum Simulations ◽  
Macroscopic Quantum Phenomena ◽  
Microcavity Polaritons ◽  
Quantum Phenomena ◽  
The One

Microcavity polaritons have demonstrated their unique propensity to host macroscopic quantum phenomena. While they appear to be highly promising for applications in a classical realm, they are still far from competing even with decade old electronics. Another playground where polaritons could emerge as strong contenders is the microscopic quantum regime with single-particle effects and nonlinearities at the one-polariton level. Several theoretical proposals exist to explore polariton blockade mechanisms, realize sophisticated quantum phase transitions, implement quantum simulations and/or quantum information processing, thereby opening a new page of the polariton physics when such ideas will be implemented in the laboratory.

scholarly journals Demonstrating the power of quantum computers, certification of highly entangled measurements and scalable quantum nonlocality

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Elisa Bäumer ◽  
Nicolas Gisin ◽  
Armin Tavakoli
Keyword(s):  
Quantum Computer ◽  
Outcome Measurement ◽  
Bell State ◽  
Bell Inequalities ◽  
Quantum Correlations ◽  
Entanglement Swapping ◽  
Quantum Nonlocality ◽  
Quantum Computers ◽  
Classical Models ◽  
Quantum Phenomena

AbstractIncreasingly sophisticated quantum computers motivate the exploration of their abilities in certifying genuine quantum phenomena. Here, we demonstrate the power of state-of-the-art IBM quantum computers in correlation experiments inspired by quantum networks. Our experiments feature up to 12 qubits and require the implementation of paradigmatic Bell-State Measurements for scalable entanglement-swapping. First, we demonstrate quantum correlations that defy classical models in up to nine-qubit systems while only assuming that the quantum computer operates on qubits. Harvesting these quantum advantages, we are able to certify 82 basis elements as entangled in a 512-outcome measurement. Then, we relax the qubit assumption and consider quantum nonlocality in a scenario with multiple independent entangled states arranged in a star configuration. We report quantum violations of source-independent Bell inequalities for up to ten qubits. Our results demonstrate the ability of quantum computers to outperform classical limitations and certify scalable entangled measurements.

Simulation of n-qubit quantum systems. III. Quantum operations

2007 ◽  
Vol 176 (9-10) ◽  
pp. 617-633 ◽  
Author(s):  
T. Radtke ◽  
S. Fritzsche
Keyword(s):  
Quantum Systems ◽  
Quantum Operations

THE TRAPPED-ION QUBIT: COHERENT CONTROL IN INFINITE-DIMENSIONAL QUANTUM SYSTEMS

2009 ◽  
Vol 24 (32) ◽  
pp. 2565-2578
Author(s):  
C. RANGAN
Keyword(s):  
Quantum Computing ◽  
Quantum System ◽  
Quantum Control ◽  
Coherent Control ◽  
Quantum Information Processing ◽  
Quantum Systems ◽  
Infinite Dimensional ◽  
Trapped Ion ◽  
Rich Variety ◽  
Control Research

Theories of quantum control have, until recently, made the assumption that the Hilbert space of a quantum system can be truncated to finite dimensions. Such truncations, which can be achieved for most quantum systems via bandwidth restrictions, have enabled the development of a rich variety of quantum control and optimal control schemes. Recent studies in quantum information processing have addressed the control of infinite-dimensional quantum systems such as the quantum states of a trapped-ion. Controllability in an infinite-dimensional quantum system is hard to prove with conventional methods, and infinite-dimensional systems provide unique challenges in designing control fields. In this paper, we will discuss the control of a popular system for quantum computing the trapped-ion qubit. This system, modeled by a spin-half particle coupled to a quantized harmonic oscillator, is an example for a surprisingly rich variety of control problems. We will show how this infinite-dimensional quantum system can be examined via the lens of the Finite Controllability Theorem, two-color STIRAP, the generalized Heisenberg system, etc. These results are important from the viewpoint of developing more efficient quantum control protocols, particularly in quantum computing systems. This work shows how one can expand the scope of quantum control research to beyond that of finite-dimensional quantum systems.

scholarly journals Comparison of the effectiveness of the Map-Reduce approach and the actor model in solving problems with high connectivity of inp data on the example of the optimization problem for a swarm of particles

2021 ◽  
pp. 049-055
Author(s):  
Larin V.O. ◽  
◽  
Provotar O.I. ◽  
Keyword(s):  
Optimization Problem ◽  
Map Reduce ◽  
Actor Model ◽  
Swarm Optimization ◽  
Memory Efficiency ◽  
Order Of Magnitude ◽  
High Connectivity ◽  
Memory Support ◽  
Bounded Input ◽  
Spark Framework

The paper defines the notion of distributed problems with bounded input components. Particle Swarm Optimization problem is shown to be an example of such a class. Such a problem's implementation based on the Map-Reduce model (implemented on the Spark framework) and an implementation based on an actor model with shared memory support (implemented on Strumok DSL) is provided. Both versions' performance assessment is conducted. The hybrid actor model is shown to be an order of magnitude more effective in time and memory efficiency than Map-Reduce implementation. Additional optimization for the hybrid actor model solution is proposed. The prospects of using the hybrid actor model for other similar problems are given

scholarly journals GENE CONVERSION AND TRANSFER OF GENETIC INFORMATION WITHIN THE INVERTED REGION OF INVERSION HETEROZYGOTES

Genetics ◽  
1973 ◽  
Vol 75 (1) ◽  
pp. 123-131
Author(s):  
Arthur Chovnick
Keyword(s):  
Information Transfer ◽  
Logical Consequence ◽  
Natural Populations ◽  
Inverted Region ◽  
Order Of Magnitude ◽  
Inversion Heterozygote ◽  
Gene Complexes ◽  
Reciprocal Transfer ◽  
Comparison Of The Results ◽  
Transfer Of Information

ABSTRACT Prior studies of recombination which monitor exchange events in exceedingly short intervals (i.e., separable sites within a cistron) reveal that the basic event in recombination involves a non-reciprocal transfer of information, termed conversion. As a logical consequence of the model suggested by the work in Drosophila, the present investigation examined recombination between rosy mutant alleles (ry:3-52.0) in Drosophila melanogaster in a paracentric inversion (In(3R)P18) heterozygote, which placed the rosy region approximately at the center of the inverted region. Comparison of the results of this study with experiments carried out in standard chromosome homozygotes reveals a dramatic suppression of classical crossovers between the rosy mutant alleles in the inversion heterozygote. However, conversions continue to occur for all rosy mutant alleles in all heterozygous combinations in the inversion heterozygote. Moreover, the order of magnitude of conversion frequencies seen in the inversion heterozygote does not change from that seen in the standard chromosome homozygote study. The significance of these observations with reference to the role of rearrangements as barriers of information transfer is discussed. Particular attention is directed to the elaborate inversion polymorphisms seen in natural populations, and to notions concerning their role in the evolution of adaptive gene complexes.

scholarly journals Feasibility of Quantum Computers in Cryogenic Systems

2020 ◽  
Vol 9 (01) ◽  
pp. 24919-24920
Author(s):  
Viplove Divyasheesh ◽  
Rakesh Jain
Keyword(s):  
Quantum Computers ◽  
Computing Power ◽  
Quantum Bits ◽  
Silicon Chips ◽  
Cool Environment ◽  
Quantum Processor ◽  
Quantum Phenomena ◽  
The Right ◽  
Electronic Controller ◽  
And Control

Quantum computers consist of a quantum processor – sets of quantum bits or qubits operating at an extremely low temperature – and a classical electronic controller to read out and control the processor. The machines utilize the unusual properties of matter at extremely small scales – the fact that a qubit, can represent “1” and “0” at the same time, a phenomenon known as superposition. (In traditional digital computing, transistors in silicon chips can exist in one of two states represented in binary by a 1 or 0 not both). Under the right conditions, computations carried out with qubits are equivalent to numerous classical computations performed in parallel, thus greatly enhancing computing power compared to today’s powerful supercomputers and the ability to solve complex problems without the sort of experiments necessary to generate quantum phenomena. this technology is unstable and needs to be stored in a cool environment for faster and more secure operation.In this paper, we discuss the possibility of integrating quantum computers with electronics at deep cryogenic temperatures.  

scholarly journals Quantum computing and second quantization

2017 ◽  
Vol 26 (03) ◽  
pp. 1741006 ◽  
Author(s):  
Hanna Makaruk
Keyword(s):  
Quantum Computing ◽  
Approximate Method ◽  
Quantum Systems ◽  
General Idea ◽  
Entangled States ◽  
Quantum Computers ◽  
Second Quantization ◽  
Particle Arrangement ◽  
The Many

Quantum computers by their nature are many particle quantum systems. Both the many-particle arrangement and being quantum are necessary for the existence of the entangled states, which are responsible for the parallelism of the quantum computers. Second quantization is a very important approximate method of describing such systems. This lecture will present the general idea of the second quantization, and discuss shortly some of the most important formulations of second quantization.

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